Greetings mbethke, and thank you for the reply.
I looked at File::Temp. But if I'm not mistaken, it creates an (altho temporary) actual copy of the file.
While this wouldn't be the "end of the earth" for me, these files are ~150Mb each.
Copy time, and space seems less efficient than using a symlink. Which is why I chose that direction.
Maybe kennethk's suggestion solves this. Then again, perhaps initiating a check at the beginning of
this script, similar to:

Greetings kennethk, and thank you for taking the time to provide this solution!
That's exactly what I was thinking. But, while having read -X, still hadn't figured out how to accomplish it in Perl.
Thanks, again. I really appreciate it.